Staphylococcus Classification • Family Micrococcaceae • Genus Micrococcus and Staphylococcus • Species more than 20 specie s S. aureus S. saprophyticus S.
Download ReportTranscript Staphylococcus Classification • Family Micrococcaceae • Genus Micrococcus and Staphylococcus • Species more than 20 specie s S. aureus S. saprophyticus S.
Staphylococcus Classification • Family Micrococcaceae • Genus Micrococcus and Staphylococcus • Species more than 20 specie s S. aureus S. saprophyticus S. epidermidis M. luteus Gram-Positive Cocci FAMILY Streptococcaceae (catalase negative) Group A: -hemolytic Streptococcus pyogenes Group B: -hemolytic (occasionally or ) S. agalactiae Group C: -hemolytic ( or ) S. anginosus, S. equismilis Group D: or hemolytic () S. bovis Group F: -hemolytic S. anginosus Group G: -hemolytic S. anginosus Viridans streptococci: (no group specific CHO) or hemolytic S. mutans and S. salivarius, S. sanguis, S. mitis and S. milleri groups Streptococcus pneumoniae (no group CHO)(-hemolytic) Enterococcus (Group D CHO) hemolytic ( or ) Enterococcus faecalis, E. faecium FAMILY Micrococcaceae (catalase positive) Coagulase-positive Staphylococcus aureus Coag.-neg. Staphylococcus epidermidis, S. saprophyticus Morphology Morphology Staph vs. Strep Gram-positive cocci in clusters Staphylococcus Streptococcus Staphylococcus See Overheads ~~~~~~~~~~ TSS Foodborne Intoxication ~~~~~~~~~~ MICROBIAL PATHOGEN Staphylococcus aureus Staphylococcus spp. Group A Streptococcus Streptococcus pneumoniae Escherichia coli Other Enterobacteriaceae Neisseria gonorrhoeae Treponema pallidum Chlamydia spp. Mycoplasma pneumoniae Vibrio cholerae ADHESIN RECEPTOR Lipoteichoic acid Unknown Slime layer Unknown LTA-M protein complex Fibronectin Protein Type 1 fimbriae CFA 1 fimbriae P fimbriae Type 1 fimbriae Fimbriae P1, P2, P3 Cell surface lectin Protein P1 Type 4 pili N-acetylhexosamine-gal D-Mannose GM ganglioside P blood grp glycolipid D-Mannose GD1 ganglioside Fibronectin N-acetylglucosamine Sialic acid Fucose and mannose Cell-Associated Virulence Factors • Capsule or slime layer (glycocalyx) • Peptidoglycan (PG) • Teichoic acid is covalently linked to PG and is species specific: S. aureus S. epidermidis ribitol teichoic acid (polysaccharide A) glycerol teichoic acid (polysaccharide B) • Protein A is covalently linked to PG • Clumping factor (bound coagulase) Virulence Factors Extracellular Enzymes • Coagulases (bound or free) Antigenic • Hyaluronidase “spreading factor” of S. aureus • Nuclease Cleaves DNA and RNA in S. aureus • Protease Staphylokinase (fibrinolysin) • Lipases • Esterases Virulence Factors: Exotoxins • Cytolytic (cytotoxins; cytolysins) Alpha toxin - hemolysin • Reacts with RBCs Beta toxin • Sphingomyelinase Gamma toxin • Hemolytic activity Delta toxin • Cytopathic for: – – – – – RBCs Macrophages Lymphocytes Neutrophils Platelets • Enterotoxic activity Leukocidin Virulence Factors: Exotoxins • Enterotoxin • Exfoliative toxin (epidermolytic toxin) • Pyrogenic exotoxins Pathogenesis • Pass skin – first line of defense Benign infection • Phagocytosis • Antibody • Inflammatory response Chronic infections • Delayed hypersensitivity Clinical Manifestations/Disease • SKIN folliculitis boils (furuncles) carbuncles impetigo (bullous & pustular) scalded skin syndrome •Neonates and children under 4 years Clinical Manifestations/Disease • Other infections Primary staphylococcal pneumonia Food poisoning vs. foodborne disease Toxic shock syndrome Metastatic Infections •Bacteremia •Osteomyelitis disease of growing bone • Pulmonary and cardiovascular infection Coagulase-Negative Staphylococci • Staphylococcus epidermidis • S. saprophyticus Staphylococcal Lab ID & Diagnostic Tests • Microscopic • Lab isolation • Coagulase positive S. aureus Mannitol Salts Agar (MSA) Staphylococcus aureus Differential Characteristics Catalase 2H2O2 O2 + 2H2O Streptococci vs. Staphylococci Catalase POS Staphylococcus Catalase NEG Differential Characteristics S. aureus Coagulase Fibrinogen Fibrin Staphylococcus aureus Coagulase POS Coagulase NEG Treatment • Drain infected area • Deep/metastatic infections semi-synthetic penicllins cephalosporins erythromycin clindamycin • Endocarditis semi-synthetic penicillin + an aminoglycoside Prevention • Carrier status prevents complete control • Proper hygiene, segregation of carrier from highly susceptible individuals • Good aseptic techniques when handling surgical instruments • Control of nosocomial infections REVIEW Gram-Positive Cocci FAMILY Streptococcaceae (catalase negative) Group A: -hemolytic Streptococcus pyogenes Group B: -hemolytic (occasionally or ) S. agalactiae Group C: -hemolytic ( or ) S. anginosus, S. equismilis Group D: or hemolytic () S. bovis Group F: -hemolytic S. anginosus Group G: -hemolytic S. anginosus Viridans streptococci: (no group specific CHO) or hemolytic S. mutans and S. salivarius, S. sanguis, S. mitis and S. milleri groups Streptococcus pneumoniae (no group CHO)(-hemolytic) Enterococcus (Group D CHO) hemolytic ( or ) Enterococcus faecalis, E. faecium FAMILY Micrococcaceae (catalase positive) Coagulase-positive Staphylococcus aureus Coag.-neg. Staphylococcus epidermidis, S. saprophyticus REVIEW Which features are only found in S. aureus? S. aureus S. epidermidis REVIEW REVIEW REVIEW REVIEW REVIEW REVIEW